The present invention relates to a fuel injector for use in an internal combustion engine.
Fuel injectors for use in an in-cylinder injection type engine include a device that is so designed as to ensure that, as set forth in Japanese Application Patent Laid-Open Publication No. Hei 11-159421, the marginal portions of the fuel injection hole exit form an oblique plane not transverse to the body axial line of the fuel injector, that the force for restraining the flow of the fuel in the radial direction of the injection hole changes in a circumferential direction, and that the reach of the fuel spray which has been injected from injection hole marginal portions having a small restraint force is long and the reach of the fuel spray which has been injected from injection hole marginal portions having a large restraint force is short. In this case, the spray is stabilized and the fuel is supplied in the direction of the ignition plug, with the result that the stability of stratified combustion is ensured.
In the injection of fuel for producing a homogeneous combustion, it is important for the injected fuel to be sufficiently mixed with air during the period up to ignition. To achieve this, therefore, there arises the need for the distribution of the flow rate to be adjustable between the fuel sprayed towards the ignition plug of the combustion chamber after being injected, and the fuel sprayed towards the piston.
The fuel injectors in prior art, however, are intended to improve combustion stability by making it easy for the fuel to reach the ignition plugs principally during stratified combustion, and no fuel injectors have been known heretofore that are designed so that the flow rate distribution ratio of the fuel injected and sprayed for the air intake stroke occurring during homogeneous combustion differs between fuel spraying towards the piston and fuel spraying towards the ignition plug.